UNIVERSITY    OF    CALIFORNIA     AGRICULTURAL    EXPERIMENT   STATION 
COLLEGE   OF  AGRICULTURE  BENJ    'DE  WHEEL"'  '—.«■«" 

THOMAS    FORSYTH    HUNT,   Dean  and  Director 
BERKELEY  H.    E.   VAN    NORMAN,   vice-Director   and   Dean 

University  Farm  School 


CIRCULAR  No.  172 
September,  1917 


WHEAT  CULTURE 

By  J.  W.  GILMOEE 


The  Food  Control  Bill  recently  passed  by  Congress  establishes  the 
minimum  price  of  first  grade  Northern  Spring  Wheat  at  two. dollars 
per  bushel.  This  gives  the  farmer  an  outlook  regarding  the  demands 
for  wheat,  and  regarding  his  share  in  the  sale  of  this  product  during 
the  period  of  the  war. 

During  recent  years  the  acreage  of  wheat  in  California  has 
materially  declined,  partly  in  favor  of  barley  and  other  crops  and 
partly  because  much  land  that  was  formerly  cultivated  has  become 
unprofitable  when  planted  to  this  crop. 

Much  has  been  learned  in  recent  years  concerning  the  diminishing 
productiveness  of  wheat  lands  and  in  a  number  of  instances  the 
information  thus  gained  has  been  applied  with  good  results.  The 
application  of  this  information  towards  the  increase  in  production 
per  acre  as  well  as  the  extension  of  the  area  in  wheat  may  be  indicated 
along  the  following  lines : 

Proper  and  timely  preparation  of  the  land  for  planting. 
Importance  and  methods  of  maintaining  the  organic  matter  in 

the  soil. 
Choice  of  seed  respecting  both  the  variety  and  quality. 
Timeliness  and  manner  of  planting  the  crop. 
Time,  methods,  and  kinds  of  fertilization. 
Timeliness  and  methods  of  harvesting  .and  handling  the  crop. 

Special  attention  is  directed  to  this  presentation  of  facts,  for  by 
studying  it  one  may  get  a  comprehensive  notion  of  the  several  ways 
by  which  the  production  of  wheat  may  be  increased.  It  is  the  design 
of  this  circular  to  elaborate  these  topics  and  to  lay  emphasis  on  the 
practical  bearing  of  the  data  in  hand. 


r  PREPARATION  OF  THE  LAND 

It  must  be  recognized  at  the  outset  that  most  of  our  grain  lands 
will  have  to  be  cultivated  under  a  deficiency  of  rainfall  for  the  maxi- 
mum production  of  crops,  hence  methods  of  increasing  the  moisture 
holding  capacity  of  the  soil  and  of  conserving  the  moisture  when 
present  are  of  much  importance.  The  usual  method  employed  to 
attain  these  ends  is  to  summer  fallow.  When  this  is  properly  carried 
out  good  results  may  be  expected. 

Time  to  Plow. — A  properly  prepared  summer  fallow  accomplishes 
three  purposes — it  prepares  the  land  for  seasonable  planting,  it  con- 
serves moisture,  and  it  induces  the  elaboration  of  available  nitrates. 
Hence,  for  both  annual  and  biennial  cropping,  as  long  a  period  as 
possible  should  intervene  between  the  time  of  plowing  and  planting. 
Ideally  the  ground  should  be  disked  and  cross-disked  as  soon  as  pos- 
sible after  the  removal  of  the  previous  crop.  This  should  be  followed 
by  plowing  to  a  depth  of  from  five  to  eight  inches,  the  time  depending 
on  the  type  and  condition  of  the  soil.  The  ground  will  break  up  more 
loosely  and  easily  under  this  procedure  than  otherwise  and  thus  give 
more  time  for  the  proper  aeration  of  the  soil  during  the  remainder 
of  the  season.  This  plowing  should  be  followed  immediately  by  suit- 
able implements  for  crushing  the  clods  and  pulverizing  the  surface, 
for  if  the  soil  is  left  rough  little  is  accomplished  in  the  way  of  con- 
serving moisture.  The  danger  of  leaving  the  plowing  until  the  winter 
rains  commence  is  that  it  may  not  be  done  until  late  in  the  season 
and  the  result  will  be  either  poor  preparation  or  too  late  a  planting 
of  the  crop. 

Depth  to  Plow. — One  reason  for  the  declining  yields  of  wheat  in 
California  is  that  much  of  the  land  has  either  been  plowed  too  shallow 
or  only  disked.  In  some  instances  this  has  been  the  practice  for  so 
many  consecutive  years  that  the  land  has  lapsed  into  poor  physical 
condition  accompanied  by  a  plow  sole  and  poor  drainage.  Most 
California  grain  lands  have  no  unproductive  subsoil  within  reach  of 
the  plow,  hence  with  few  exceptions  deep  plowing  may  be  practiced 
without  fear  of  bringing  inert  subsoil  to  the  surface.  During  three 
years  at  the  University  Farm,  Davis,  plowing  eight  inches  deep  as 
contrasted  with  four  inches  resulted  in  an  increase  in  the  yield  of 
wheat  of  37.4  per  cent. 

Deep  plowing  is  the  more  effective,  the  earlier  it  is  accomplished. 
If  plowing  is  delayed  until  after  the  middle  of  December  a  shallow 
plowing  for  that  year  with  thorough  surface  working  will  produce 
better  results.     Deep  plowing  after  the  middle  of  December  generally 


results  in  a  loose  soil  that  does  not  have  moisture-retaining  capacity 
and  a  physical  condition  that  is  detrimental  to  root  development. 

The  exact  depth  to  plow  will  vary  with  the  time  and  the  character 
of  the  soil.  Dry  plowing  is  more  expensive  than  that  done  when  the 
soil  is  in  optimum  moisture  condition  and  the  heavy  soils  may  not 
be  plowed  so  deeply  with  the  same  beneficial  results  as  the  lighter 
ones.  General  practice  has  shown  that  plowing  to  a  depth  of  about 
eight  inches  results  in  the  best  returns  per  unit  of  labor  expended. 

The  land  should  be  brought  to  a  smooth,  well-pulverized  surface 
as  soon  after  plowing  as  possible.  The  making  of  this  surface  will 
usually  compact  the  subsurface  to  the  consistency  which  is  desirable 
for  the  uniform  and  quick  germination  of  the  seed  when  planted. 

MAINTENANCE    OF    ORGANIC    MATTER 

More  thorough  cultivation  usually  results  in  a  more  rapid  depletion 
of  the  organic  matter  in  the  soil.  There  results  from  this  an  increased 
amount  of  available  nitrogen  in  the  soil  and  hence  increased  crop 
yields.  One  may  not,  therefore,  expect  to  produce  crop  yields  by 
thorough  cultivation  without  at  the  same  time  decreasing  the  organic 
matter  in  the  soil.  It  has  been  found  as  the  average  of  a  number 
of  tests  that  the  available  nitrogen  in  well-prepared  and  cultivated 
fallow  was  more  than  200  per  cent  greater  than  that  in  a  rough  fallow 
and  more  than  50  per  cent  greater  than  that  in  unplowed  stubble. 
It  is  essential,  therefore,  under  better  culture  methods  to  put  forth 
additional  efforts  in  maintaining  the  organic  matter  content  of  the 
soil.  This  can  be  done  by  applying  yard  manure  or  other  well-rotted 
litter  to  the  land  in  the  fall  to  be  turned  under,  or  it  may  be  accom- 
plished by  growing  a  cover  crop  on  the  land  every  second,  third,  or 
fourth  winter,  according  to  the  needs  of  the  land  and  the  costs  thereof. 
It  requires  moisture  to  rot  vegetable  material  as  well  as  to  grow 
crops.  Hence,  where  moisture  is  a  limiting  factor,  one  must  exercise 
caution  in  plowing  into  the  soil  dry  unrotted  vegetable  material. 

Cover  Crops. — On  the  whole  the  use  of  cover  crops  is  most  advan- 
tageous and  is  perhaps  cheapest  in  the  long  run.  This  experiment 
station  has  already  conducted  experiments  sufficiently  diversified  re- 
garding time  and  soil  to  show  that  the  yield  of  wheat  is  oftentimes 
more  than  doubled  by  the  use  of  cover  crops. 

The  procedure  in  this  operation '  is  briefly  as  follows :  The  land 
is  prepared  in  the  fall  as  for  a  good  summer  fallow.  As  soon  as  there 
is  sufficient  moisture  in  the  soil  for  quick  and  uniform  germination 
of  the  seed  the  cover  crop  should  be  planted.  In  no  case  is  it  ad- 
vantageous to  plant  a  cover  crop  later  than  the  middle  of  December, 
for  under  such  circumstances  the  crop  would  not  make  sufficient 
growth  to  be  worth  while.  Where  irrigation  is  possible,  a  more 
satisfactory  growth  would  be  obtained  by  planting  before  the  first 
of  November.  This  operation  should  not  be  delayed,  for  an  abundant 
growth  is  desired  and  this  crop  should  be  started  early.     Horse  beans, 


fenugreek,  Canada  field  peas,  rye  and  vetch,  and  vetch  and  rye  each 
alone  have  been  planted  under  varying  conditions.  On  the  lighter 
soils  rye,  and  rye  and  vetch  combined  seem  to  do  best,  while  on  the 
heavier  soils  the  horse  beans  and  fenugreek  are  best.  The  cover 
crop  should  be  turned  under  from  eight  to  ten  inches  deep  before  the 
plants  are  sufficiently  dry  to  require  additional  water  to  rot  them. 
A  thorough  disking  before  turning  under  will  facilitate  rotting  and 
the  soil  should  be  well  compacted  immediately  afterwards  in  order 
to  %get  good  contact  with  the  green  material.  The  land  is  then  kept 
in  good  tilth  and  free  from  weeds  and  planted  to  wheat  the  following 
December.  In  most  instances  where  organic  matter  is  deficient  it  is 
important  to  furnish  quantity  as  well  as  quality.  As  stated  above, 
this  procedure  may  be  repeated  every  third  or  fourth  winter  and 
included  as  a  part  of  the  summer  fallowing  as  the  conditions  seem  to 
require.  By  using  a  cover  crop  in  the  system  of  wheat-growing  it  is 
possible  in  some  instances  to  postpone  the  summer  fallow  to  the  third 
or  fourth  year  of  the  cycle.  It  is  safe  to  say  that  the  cumulative  yield 
over  five  to  eight  years  will  exceed  the  total  yield  of  continuously 
cropped  land  and  pay  for  the  cover  crop  in  addition. 

GOOD   SEED 

Varieties. — Excellent  preparation  of  the  soil  and  an  optimum 
organic  matter  content,  however,  are  no  complete  assurances  of  the 
largest  yields  possible.  It  still  remains  to  secure  good  seed.  Two 
qualities  characterize  good  seed  wheat,  viz.,  adaptability  and  produc- 
tiveness, assuming  of  course  that  the  variety  has  reasonably  good 
milling  qualities.  In  the  final  analysis  of  the  question  the  best 
variety  for  any  farmer  to  grow  is  a  local  problem;  for  local  climate, 
soil,  and  culture  methods  bear  more  directly  on  yields  for  a  series  of 
years  than  do  other  factors.  Therefore,  every  farmer  ought  to  grow 
several  varieties,  some  of  them  on  a  small  scale,  until  he  has  ascer- 
tained the  best  for  his  own  conditions.  The  following  list  shows  those 
varieties  which  have  good  milling  qualities  and  which  have  for  a 
series  of  years  given  good  yields  at  the  University  Farm : 

Yield,  lbs. 
Variety  Years  trial  per  acre 

Propo   6  2911.26 

Kings  Early  8  2855.4 

Early  Baart   6  2486.4 

Defiance  5  2448.6 

White    Australian    8  2433.6 

Cumberland  6  2346.6 

University  Gem   4  2134.2 

Galgalos  6  2070.0 

Federation  5  1953.6 

In  the  following  list  are  indicated  the  varieties  that  do  well  in  the 
respective  counties.  It  is  not  stated  that  other  varieties  would  not 
do  well,  but  where  there  is  any  doubt  about  a  variety,  those  indicated 
will  yield  as  well  as  any: 


Best  wheats  for  California : 


Santa  Barbara 
Ventura 
Los  Angeles 
Orange 
San  Diego 


>    Coast,  Defiance;  interior,  Sonora. 


Imperial  (irrigated),  Bobs,  White  Australian,  Sonora. 


Eiverside 

San  Bernardino 

Kern 

Tulare 

Kings 


>,    Sonora 


San  Luis  Obispo  1 

Monterey  y    Propo,  Galgalos. 

San  Benito  j 


Fresno 
Madera 
Merced 
Stanislaus 
San  Joaquin 

Solano 

Sacramento 

Yolo 

Sutter 

Yuba 

Colusa 

Butte 

Glenn 

Tehama 

Modoc 
Lassen 
Siskiyou 


Early  planting,  White  Australian. 
Late  planting,  Early  Baart,  Sonora. 


White  Australian,  Little  Club,  Early  Baart. 


Fall  seeding,  Turkey. 

Spring    seeding,    White    Australian,    Galgalos,    Cali- 
fornia Gem. 


The  productiveness  of  good  seed  wheat  depends  upon  a  number 
of  conditions.  It  should  be  clean  and  free  from  weed  seeds,  it  should 
be  large  and  plump,  and  it  should  be  selected  only  from  those  fields 
where  conditions  of  growth  and  development  are  best.  Farmers 
sometimes  complain  that  seed  wheat  runs  out  or  becomes  unproduc- 
tive. This  may  be  the  case  when  no  attention  is  paid  to  maintaining 
its  good  qualities  by  selection  and  grading.  "When  properly  grown, 
selected  and  graded,  home-grown  seed  wheat  is,  for  a  series  of  years, 
most  productive.  The  advantage  in  yield  from  planting  large,  heavy 
seed  ranges  sometimes  as  high  as  20  per  cent  when  compared  with  the 
crop  from  small,  light  seed.  Every  wheat  farmer  should  select  those 
portions  of  his  fields  which  produce,  all  things  considered,  the  best  crop. 


The  threshed  grain  should  be  thoroughly  recleaned  by  means  of  an 
ordinary  fanning  mill  prior  to  seeding.  The  matter  of  seed  selection 
can  be  carried  out  farther  than  this,  but  this  method  will  bring  good 
results  and  can  be  carried  out  on  practically  every  farm. 

Smut. — Seed  wheat  should  also  be  free  from  smut,  or  if  smut 
spores  be  present  it  should  be  treated  so  as  to  prevent  the  develop- 
ment of  the  disease.  Losses  as  high  as  15  per  cent  are  sometimes 
caused  by  this  disease,  but  by  proper  treatment  these  losses  may  be 
reduced  to  almost  nothing.  Either  of  two  methods  may  be  employed, 
as  follows : 

A.  Formalin  Method. — Make  a  solution  of  40  per  cent  formalin, 
one  pound  to  forty  gallons  of  water.  The  wheat  may  be  dipped  into 
this  solution  in  bags  or  wire  baskets  for  a  period  of  ten  minutes,  and 
then  spread  in  the  shade  to  dry.  If  large  quantities  are  to  be  treated 
it  is  both  handy  and  effective  to  pile  the  grain  and  sprinkle  or  spray 
the  solution  upon  it  until  every  grain  is  wet.  Thoroughly  wetting 
every  grain  is  very  important,  and  this  may  be  facilitated  by  stirring 
the  pile  with  a  shovel  or  rake  as  the  spraying  continues.  After 
thoroughly  spraying,  it  may  be  spread  in  the  shade  to  dry. 

B.  Copper  Sulphate  Method. — The  solution  for  this  method  is 
made  by  dissolving  one  pound  of  copper  sulphate  in  four  gallons  of 
water.  The  procedure  and  time  of  treatment  is  the  same  as  for  the 
formalin  method. 

PLANTING  THE   CROP 

Time  of  Seeding. — A  survey  of  the  wheat  conditions  in  both  the 
great  valleys  this  year  emphasized  the  importance  of  timely  planting. 
In  practically  all  instances  where  a  wheat  crop  was  poor  the  reason 
was  found  to  be  improper  preparation  of  the  land,  or  late  planting. 
Even  where  the  rainfall  was  not  up  to  normal  and  the  season  was 
cold,  crops  were  good  where  the  preparation  of  the  land  was  good 
and  planting  timely.  Barring  a  few  exceptional  conditions  the  best 
crops  of  wheat  are  produced  from  plantings  made  about  December  1. 
If  planted  late  in  December  or  later  the  crop  will  not  have  sufficient 
time  to  develop  its  roots  and  crown  before  growing  weather  comes  in 
the  spring  and  its  ripening  will  be  delayed  beyond  the  period  of 
optimum  moisture  and  climatic  conditions. 

The  following  figures  show  the  influence  of  the  time  of  seeding 
on  the  yield  of  wheat  at  the  University  Farm,  1917.  The  land  was 
prepared  the  same  in  both  trials.  The  figures  represent  the  average 
of  three  plots  for  each  of  the  two  varieties. 

Yield,  Pounds  per  Acre 

Variety  Seeded  Seeded  Seeded 

Dec.  15  Jan.  19  Mar.  3 

Defiance    3754  1467  1508 

Sonora  3825  1742  1178 

Sometimes  wheat  may  be  planted  in  the  dry  soil  before  the  fall 
rains  set  in.      The  advantage  of  this  practice  is,  especially  on  large 


.■areas,  in  getting  the  seed  in  before  operations  are  prevented  by  the 
rains.  The  disadvantages  are  that  more  seed  per  acre  is  generally 
required  and  the  stand  and  growth  are  not  likely  to  be  uniform.  All 
things  considered  planting  is  best  accomplished  by  the  drill  and 
should  be  done  at  a  time  when  there  is  sufficient  moisture  in  the  soil 
to  give  the  seed  an  even  and  quick  germination.  When  the  land  is 
weedy,  planting  should  be  delayed  until  after  the  first  rain  in  order 
that  by  harrowing  early,  germinating  weeds  may  be  killed. 

Amount  of  Seed. — The  amount  of  seed  to  plant  depends  mainly 
on  two  conditions:  the  amount  of  rainfall  or  available  moisture,  and 
the  condition  and  productivity  of  the  soil.  Where  rainfall  is  decid- 
edly low,  say  from  ten  to  twelve  inches  and  the  soil  is  unproductive, 
the  rate  should  be  forty  to  fifty  pounds  per  acre.  This  amount  may 
be  increased  to  ninety  to  one  hundred  pounds  where  rainfall  is  above 
twenty  inches  and  the  soil  productive  and  in  good  condition.  The 
larger  amount  is  especially  practicable  where  the  planting  is  on  good 
summer  fallow  or  following  alfalfa,  or  a  cover  crop.  Where  the  seed 
is  planted  by  broadcasting,  these  amounts  should  be  increased  by 
15  per  cent. 

FERTILIZATION 

Reference  has  already  been  made  to  depleted  yields  of  wheat  on 
continuously  cropped  lands.  In  man}^  instances  this  is  due  to  im- 
proper physical  condition  of  the  soil,  but  sometimes  it  is  due  to  lack 
of  suitable  available  plant  food.  Investigations  for  several  years 
past  indicate  that  in  most  instances  the  trouble  arises  from  a  lack  of 
sufficient  available  nitrates  at  all  times  during  the  season  of  growth. 
Fertilizer  trials  near  Stockton  this  year  show  that  250  pounds  of 
sulfate  of  ammonia  applied  at  the  time  of  planting  produced  a  yield 
of  1764  pounds  of  wheat  per  acre  compared  to  947  pounds  of  wheat 
per  acre  from  the  adjacent  plot  untreated.  Additional  information 
on  this  experiment  is  presented  in  the  following  table : 

Plot  Treatment  Yield, 

Lbs.  per  acre 

;                 <6  50  lbs.  N.  from  sulphate  of  ammonia 1764 

7                7  Check  947 

1                 '9  50  lbs.  N.  from  nitrate  of  soda 1410 

10  Check  1176 

19  Check  1069 

20  Complete  fertilizer  with  lime 1624 

24  Potash  and  phosphoric  acid  with  organic  matter       1507 

25  Check  809 

Average   of   treated   plots 1574 

Average  of  check  plots 1000 

On  a  field  of  sandy  soil  near  Glendale  (Los  Angeles  County) 
sulphate  of  ammonia  was  applied  to  the  growing  grain  on  February 
11  at  the  rate  of  200  pounds  per  acre  and  the  yield  of  wheat  was 
increased  from  822  pounds  per  acre  to  2114  pounds  per  a  ere ;  an 


8 

increase  of  157  per  cent.  These  are  outstanding  instances,  but  they 
emphasize  the  fact  that,  especially  on  lands  that  are  unproductive 
because  of  poor  soil,  it  pays  to  apply  fertilizers  containing  available 
nitrogen. 

Additional  data  on  this  experiment  appears  in  the  following  table : 

Fertilized         Unfertilized  increase 

Per  cent 

Number  of  head-bearing  culms 4680  2387  96.4 

Weight  of  heads,  grams 3741  1457.1  156.7 

Weighted  average  length  of  culms 67.92  58.25  16.6 

Sterile  spikelets  per  head 3.35  5.11  52.4* 

Average  number  of  grains  per  head 19.87  16.65  19.3 

Weight  per  1000  heads,  grams 799.3  610.4  30.9 

Average  weight  of  grain  per  head,  grams .5881  .4484  31.1 

Weight  per  100  grains,  grams 31.606  30.105  4.98 

Percentage  of  grain  to  total  weight  of  culms  .4051  .3847  .53 

*  Decrease. 

The  time  to  apply  this  fertilizer  depends  on  various  conditions, 
but  probably  in  most  instances  it  should  be  applied  at  the  time  of 
planting.  Where  sulfate  of  ammonia  or  nitrate  of  soda  is  used  a 
portion  of  this  may  be  applied  in  late  January  or  early  February, 
especially  on  those  portions  of  the  field  that  may  indicate  by  the 
color  or  growth  of  the  grain  the  need  of  additional  nitrogen.  The 
importance  of  proper  fertilization  is  especially  emphasized  because 
it  is  desirable  to  increase  the  yield  at  this  time  as  much  as  possible. 

IRRIGATION 

Most  wheat  in  California  is  grown  without  irrigation.  However, 
where  water  is  available  and  the  land  is  adaptable  one  irrigation  may 
be  given  during  the  early  growth  of  the  crop,  for  water  is  not  so 
much  needed  for  other  crops  at  that  time.  There  are  parts  of  Cali- 
fornia, especially  in  the  Imperial  and  southern  San  Joaquin  valleys, 
and  in  localities  in  the  northeastern  part  of  the  state  where  wheat 
may  be  grown  only  by  irrigation.  In  irrigating  wheat  the  principal 
points  on  which  information  is  desired  are  the  amount  of  water  to 
use  and  the  times  of  application.  The  practice  on  both  of  these  points 
will  vary  according  to  a  number  of  conditions  such  as  precipitation, 
soil  porosity  and  depth,  and  the  temperature  and  dryness  of  the  air 
which  controls  evaporation.  In  general,  and  especially  where  irri- 
gation must  be  depended  upon  entirely,  three  irrigations  of  about 
five  acre-inches  each  have  produced  best  results.  This  water  should 
be  applied  at  the  five-leaf  stage,  when  the  head  is  in  the  boot,  and 
at  the  stage  of  blossom.  "Where  only  one  or  two  irrigations  can  be 
given  the  water  should  be  applied  at  the  first  and  second  periods, 
respectively. 

Germinating  and  starting  wheat  by  irrigation  has  not  been  found 
a  good  practice  because  it  leaves  the  soil  in  a  compact  and  crusted 
condition.  This  condition  is  not  conducive  to  the  subsequent  normal 
development  of  the  plant. 


